Different types of expanders/turbines are known for converting thermal energy into electrical and/or mechanical energy through an Organic Rankine Cycle (ORC) and/or a Kalina cycle. Among the best known types the axial expanders and radial expanders with one or more stages in series are to be mentioned.
Generally, a turbine of known type is made up of a fixed body, referred to as stator, and a movable part, referred to as rotor. The turbine's rotor part consists of a shaft to which one or more expansion stages of the working fluid are fastened. Assembly of the rotor and stator parts is carried out through a mechanical unit ensuring the almost complete nullity of the relative movements of the rotor and stator parts, except for rotation around the revolution axis coincident with the machine's shaft.
The public document WO2010/106570A1 depicts the structure of a turbine for gas and/or steam expansion comprising a case having a stated transit periphery of a working fluid between an inlet opening and an outlet opening, at least one stator, a turbine shaft rotating around an axis and carrying at least one rotor, an outer short-pipe frontally protruding from said case and coaxial with the turbine shaft. Interposed between the outer short-pipe and the turbine is a supporting unit that can be axially extracted from the short-pipe in a unitary form and keeps the shaft fastened to the rotor. Documents U.S. Pat. No. 2,881,972, WO2005/042924, GB822173, DE102008056061, WO01/86130, U.S. Pat. No. 3,612,628, FR2487459, U.S. Pat. No. 4,285,632 show other examples of turbines with extractable parts.